1. Field of the Invention
The present invention relates to a process for coating a resist liquid on a substrate, such as semiconductor wafers or LCD substrates (glass substrates for Liquid Crystal Displays), and also relates to a coating and developing apparatus and a coating and developing method for performing a developing process after exposure.
2. Background Art
In a process for producing semiconductor devices and LCD substrates, formation of a resist pattern on each substrate is performed employing a technique called photolithography. For example, this technique is achieved through a series of steps including: coating a resist liquid on each substrate, such as a semiconductor wafer (hereinafter referred to as a wafer) so as to form a resist liquid film on the substrate of the wafer, exposing the resist film with a photo-mask, and performing a developing process to obtain a desired pattern.
This process is generally carried out by using a resist pattern forming apparatus including a coating and developing apparatus for performing coating and developing a resist liquid, and an exposing apparatus. As such an apparatus, for example, an apparatus disclosed in Patent Document No. 1 is known, wherein, as shown in FIG. 16, for example, a carrier 10 containing plural sheets of wafers W is carried in a carrier stage 11 of a carrier block 1A, and each wafer W in the carrier 10 is then transferred to a processing block 1B via a transfer arm 12. Thereafter, the wafer W is carried into a coating unit 13A in the processing block 1B, a resist liquid is coated thereon, and the wafer W is carried into an exposing apparatus 1D via an interface block 1C.
After the exposing process, the wafer W is returned to the processing block 1B, subjected to a developing process in a developing unit 13B, and then returned to the original carrier 10. In the drawing, reference numerals 14 (14a to 14c) respectively designate rack units each comprising a heating unit, a cooling unit, a hydrophobicity rendering unit, a transferring stage or the like, for providing a predetermined heating process or cooling process to each wafer before and after the process in the coating unit 13A or developing unit 13B. The wafer W is carried between modules including the coating unit 13A, developing unit 13B and rack units 14a to 14c due to two carrying means 15A, 15B provided in the processing block 1B. Namely, in the processing block 1B, the wafer W is carried between the modules into which the wafer W is successively fed.
Depending on types of the resist film to be formed, in the case where the resist film and an antireflection film are laminated on the wafer W, or in the case where only the resist film is formed but the antireflection film is not formed on the waver W, or in the case where the antireflection film is formed prior to providing the resist film or coating the resist liquid on the wafer W, the hydrophobicity rendering process may be necessary or unnecessary. Also, the coating unit and hydrophobicity rendering unit must be changed to accommodate each lot with alteration of such film forming conditions.
In this case, if providing, in each processing block, all modules required for a coating process for forming an intended resist film, including a coating unit, a developing unit, a hydrophobicity rendering unit, a heating unit, a cooling unit and the like, in accordance with each coating mode, the number of modules to be incorporated in one processing block is significantly increased. Thus, if carrying wafers W by using a common carrying system through such a processing block, the number of modules to be accessed becomes quite greater, thus rendering obtainment of higher throughput difficult.
The present inventor has attempted to enhance throughput of the coating and developing apparatus by vertically dividing a processing block into one area for performing a coating process by housing modules to be employed prior to the exposing process in the area and the other area for performing a developing process by housing modules to be employed after the exposing process therein. In addition, by providing carrying means in the respective areas, it has been attempted to reduce the load on each carrying means and enhance carrying efficiency, thereby enhancing the throughput of the coating and developing apparatus. This vertical arrangement of the one area for performing the coating process and the other area for performing the developing process as well as the provision of carrying means for the respective areas are described in Patent Document 2.
However, even also in the Patent Document 2, if providing, all modules required for a coating process, such as a coating unit, a unit for forming an antireflection film, a hydrophobicity rendering unit and the like, in the area of performing the coating process, the number of modules to be incorporated in the area for performing the coating process is significantly increased. Therefore, the load imposed on the carrying means for this area becomes still greater, thus rendering achievement of higher throughput considerably difficult.
Additionally, in such a configuration that the area for performing the coating process and the area for performing the developing process are vertically arranged, each area must be thinned to some extent. Therefore, when incorporating modules in such areas in a multi-staged fashion, the number of modules to be incorporated can not be increased as desired. Namely, the number of modules to be provided in each area is significantly restricted. Additionally, in the area for performing the resist coating process, in order to enhance the throughput, it is desired to increase the number of heating units for performing heating processes after coating the resist liquid. However, in the area for performing the coating process, adding to these heating units, it is also necessary to incorporate a hydrophobicity rendering unit, a cooling unit, a periphery exposing apparatus and the like. Therefore, in reality, it is quite difficult to increase the number of heating units as desired.
Patent Document 1:
    TOKUKAI No. 2004-193597, KOHOPatent Document 2:    Japanese Patent No. 3337677, KOHO